<!DOCTYPE html>
<html lang="en">
<head>
   <meta charset="UTF-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <meta http-equiv="X-UA-Compatible" content="ie=edge">
   <title>链模式</title>
      <script src="https://cdn.bootcss.com/jquery/1.11.3/jquery.js"></script>
      
</head>
<body>
      <h1 id="demo">链模式</h1>
      <p id="test">ces</p>
      <script src="index8.js"></script>

      <script>
        //jquery
        console.log('jquery:',$('#test'));
      </script>
</body>
</html>